The specialty of palliative medicine started in the late 1980s with the recognition that controlling symptoms, including pain, was an important element in all chronic diseases regardless of the phase, be it stable, symptomatic or final:
Stable or initial phase – The patient experiences few symptoms and longevity ranges from years to months, as with dementia or motor neuron disease.
Symptomatic phase – This phase is characterized by a worsening of the underlying disease, associated with frequent symptoms and a survival of months to weeks.
Final or terminal phase – This is the end-of-life phase, during which survival is measured in weeks to days and the control of symptoms is more difficult.
The World Health Organization defines palliative care as follows:
"Palliative care is an approach that improves the quality of life of patients and their families facing the problem associated with life-threatening illness, through the prevention and relief of suffering by means of early identification and impeccable assessment and treatment of pain and other problems, physical, psychosocial and spiritual."
It is important to recognize that palliative care does not preclude the use of other therapies to treat the underlying disease. In 2012, the American Society of Clinical Oncology (ASCO) published the following landmark provisional clinical opinion:
.This care is not solely restricted to oncology and often treats other illnesses such as advanced heart and lung diseases, neurodegenerative disorders and similar other chronic diseases which significantly impair quality of life. The use of an interprofessional team is critical in the management of all aspects of the patient and family care.